The purpose of this study was to determine the growth, yield and the potential for carbondioxide absorption of dayak onion plants given four types of manure on peat soil. This experiment used a ...completely randomized design with four treatments and six replications. The treatments tried were chicken, swallow, cow, goat manure. The results showed that the type of manure had an effect on plant growth and yield. The growth of plant height and the number of leaves dayak onion planted on peat soil given cow and goat manure grew significantly higher and more the number of leaves, the lowest was found in dayak onion plants fed with swallow manure. The highest yield was obtained on dayak onion plants fertilized with 30 t ha-1 cow manure with a tuber weight of 41.50 g clump-1, with a larger tuber diameter, but the highest number of tubers was obtained in dayak onion plants fertilized by swallow manure with tubers diameter smaller. The highest weight of biomass, stored carbon and carbon dioxide absorption were 6.6; 3.3 and 12.11 t ha-1 found in dayak onion plants planted on peat soil given cow manure 30 t ha-1
Elfiati D, Delvian, Hanum H, Susilowati A, Rachmat HH. 2021. Potential of phosphate solubilizing fungi isolated from peat soils as inoculant biofertilizer. Biodiversitas 22: 3042-3048. ...Phosphate-solubilizing fungi are the microbes that have the ability to dissolve insoluble phosphate and made it available for plants. Therefore, the purpose of this study was to obtain the phosphate-solubilizing fungi from peat soils. Peat soil samples were taken in a composite at a depth 0-20 cm from the peat ecosystem in Nagasaribu Village, Lintong Nihuta Sub-district, Humbang Hasundutan District, North Sumatra, Indonesia. Soil samples were isolated to obtain phosphate-solubilizing fungi using the Pikovskaya selective medium. The obtained isolates were tested for their ability to dissolve phosphate qualitatively by calculating the dissolution index values and quantitatively by calculating the available phosphorus on Pikovskaya medium by using four phosphate sources, namely Ca3(PO4)2, AlPO4, FePO4, and phosphate rock. Total of 12 isolates of phosphate-solubilizing fungi was obtained during the present study. Based on the results of qualitative and quantitative testing, all 12 isolates have the ability to release phosphate from the four tasted phosphate sources. The qualitative test obtains dissolution index values that vary from 2.55 to 4.25, while quantitatively, the isolates were able to dissolve phosphate in the value range from 17.77 ppm to 69.86 ppm. The top five fungal isolates with highest phosphate-solubilizing potential were FG5, FG8, FG9, FG11, and FG12. Based on molecular identification, these five isolates were identified as Aspergillus niger.
The influence of peat soil environment (PSE) on the mechanical properties of cement-soil in the area around Dianchi Lake and Erhai Lake in Yunnan Province has attracted much attention. This study ...explores the change law of cement-soil UCS in the PSE, and provides guidance for the development and sustained usage of peat soil foundation. The paper discusses the preparation of cement-soil samples by adding humic acid (HA) and cement to cohesive soil with low organic matter content (blending method) and soaking it in fulvic acid (FA) solution and deionized water (steeping method) to simulate the actual working environment of cement-soil. Unconfined compressive strength (UCS), acid consumption, ion leaching, scanning electron microscope (SEM), and X-ray diffraction (XRD) tests are carried out on cement-soil samples soaked for 90 days. The results show that HA can significantly reduce the UCS of cement-soil. FA can reduce the UCS of cement-soil when the content of HA is less than 18%. However, when the amount of HA is more than 18%, the UCS of cement-soil increases slightly. FA makes the deformation and failure type of cement-soil gradually change from brittle shear failure to plastic shear failure. FA reacts with the cement hydration products in the sample so that the cumulative acid consumption of the cement-soil sample continues to increase, and the dissolution of Ca2+, Mg2+, Al3+, and Fe3+ in the sample increases the ion concentration of the soaking solution. In addition, SEM and XRD show that HA can increase the macropores and connectivity of cement-soil, while FA fills part of the pores of the wetting layer. In the PSE, FA can strengthen the inner structure of HA particles and fill and cement the layers of cohesive particles, enhancing the construction of cement-soil with HA content greater than 18%, so that its UCS is relatively improved. However, when the amount of HA is less than 18%, there are more small pores in the cement-soil. The interaction between FA and HA in the cement-soil is weak. The influence of FA on cement-soil is mainly a weakening effect, and its UCS is relatively reduced.
Planting of concrete piles on the soil surface must reach a layer of rock/soil that is hard enough for the building to stand firmly. Rock/soil layers can be studied through geoelectric resistivity ...log data. We require tools with high prices and need a complicated process to obtain such data. Therefore, a mathematical model is developed to explore geological formations using a space-time model to overcome these problems. The generalized space-time autoregressive (GSTAR) model can be applied to the resistivity data. However, this data correlates with each rock layer. Therefore, we develop a GSTAR model for time-correlated errors. In our study, the parameter index, usually for a concrete time, is applied to the relative time in the form of rock layers. This research uses geoelectric resistivity log data at six locations in Pontianak City, namely Untan 1, Untan 2, Untan 3, Jl. Sawo, Jl KPM Permai, and Gg. Beringin. The GSTAR(1,1) model with time correlation error results in an average RMSE value of 9.51605 Ωm. In addition, we obtain that the most profound peat soil depth is 17.9 m from the surface and is located in the Untan 3.Keywords: GSTAR (1,1); martingale difference; peat soil; resistivity; time-correlated error. AbstrakPenanaman tiang pancang beton pada tanah gambut harus mencapai lapisan batuan/tanah yang cukup keras agar bangunan dapat berdiri kokoh. Lapisan batuan/tanah dapat dipelajari melalui data log resistivitas geolistrik yang memerlukan alat yang mahal dan proses yang rumit untuk mendapatkan datanya. Untuk mengatasi permasalahan tersebut, dibuatlah model matematika untuk mengeksplorasi formasi geologi menggunakan model ruang-waktu. Salah satu model yang dapat diaplikasikan adalah generalized space-time autoregressive (GSTAR). Pada umumnya, data ini memiliki korelasi antarlapisan batuan. Oleh karena itu, pada penelitian ini dikembangkan model GSTAR untuk galat yang berkorelasi waktu. Indeks parameter yang biasanya menggunakan waktu konkret, pada penelitian ini diterapkan pada waktu relatif berupa lapisan batuan. Model ini disebut GSTAR dengan galat berkorelasi waktu. Data yang digunakan adalah data resistivitas geolistrik pada enam lokasi di Kota Pontianak Indonesia yang dinamakan Untan 1, Untan 2, Untan 3, Jl. Sawo, Jl KPM Permai, dan Gg. Beringin. Hasil menunjukkan bahwa model GSTAR(1,1) dengan galat berkorelasi waktu berhasil mengestimasi nilai resistivitas geolistrik di keenam lokasi tersebut dengan nilai rata-rata geometri dari RMSE sebesar 9,51605 Ωm. Selain itu, model ini pun berhasil memperkirakan kedalaman tanah gambut terdalam (dari permukaan tanah) yang terletak di lokasi Untan 3 yaitu 17,9 m.Kata Kunci: GSTAR(1,1); pembeda martingale; tanah gambut; resistivitas; galat berkorelasi waktu. 2020MSC: 62P30
The peatlands have the potential to support food security efforts. However, there is have constraints on soil fertility, especially the P nutrients availability. The biotechnology approach, the ...application of ameliorant (biochar-compost carrier medium (biocom)) enriched with phosphate solubilizing fungi (PSF) and coal fly ash (CFA), was expected to increase the P-availability in peat soils. The research aimed to study the application of biocom enriched with PSF and CFA to increase soil P-availability and plant P-uptake. The study was conducted using peat soil media with the formulation of CFA and biocom enriched with PSF and CFA as treatments. The treatment effect was observed through soil P available and plant P uptake of maize. The results showed PSF application was inconsistent in improving P available in peat soils in Kalimantan. In Central Kalimantan, Biocom + PSF was able to increase P available in peat soils by up to 406.18% (A. oryzae-Tb7) and 353.44% (N. fischeri-Tm8). However, in South Kalimantan P available in peat soil was only 8.04% (A. oryzae-Tb7) and 12.86% (N. fischeri-Tm8). The CFA+ (biocom+PSF) formulation increased P available in Central Kalimantan peat soils, but it was different from South Kalimantan peat soils. The application of biocom+PSF and CFA has not been able to increase the P uptake of maize plant in peatlands of South Kalimantan.
•Spatial variability of hydro-physical properties of peat were investigated.•Adding macroporosity to PTFs improved the prediction of Ks and VG model parameters.•Peat degradation alters the spatial ...variance and spatial dependence of soil properties.
The spatial variability of soil properties plays an important role in water and carbon cycles in peatlands. The objectives of this study were to analyze the spatial variation of hydro-physical properties of peat soils and to establish pedotransfer functions (PTFs) to estimate the hydraulic properties of peat using readily available soil properties. We selected three study sites, each representing a different state of peat degradation (natural, degraded and extremely degraded). At each site, 72 undisturbed soil cores were collected from 5 m by 5 m grid cells in an area of 35 m by 40 m. The saturated hydraulic conductivity (Ks), soil water retention curves, total porosity, macroporosity (pore diameter >30 μm), bulk density and soil organic matter content (SOM) were determined for all sampling locations. The Van Genuchten (VG) model parameters (θs, α, and n) were optimized using the RETC software package. A strong positive correlation between macroporosity and Ks was observed irrespective of the degradation stage of the peat. However, the relationships between macroporosity and Ks differed between the natural and the drained peatlands. Adding macroporosity to the PTFs substantially improves the prediction of Ks as well as VG parameters. Results show that the soil physical and hydraulic properties (e.g. Ks and VG model parameters) exhibit different levels of spatial heterogeneity depending on the peat degradation stage. The geostatistical analysis suggests that the spatial dependence of soil hydro-physical properties varies depending on the considered property as well as land management (e.g. drainage). Bulk density and SOM are spatially dependent, whereas Ks and macroporosity are spatially independent if the peat is severely degraded. In conclusion, the peat degradation stage plays an important role and should be generally considered in the spatial analysis of peatlands. The obtained semivariograms may serve as a basis for 2D and 3D hydrological modelling as well as peatland restoration studies.
The article presents the results of research on the bioproductivity of ecologically clean waste generated during excavation work on subway construction sites and other underground construction. It is ...proposed to use waste as one of the components of soil mixture preparation. In the course of the work, soil mixtures varied in relation to the waste/peat soil. A number of laboratory experiments on the germination of a lawn grass mixture, widely used in the improvement of cities, was set up. Based on the results of the work, recommendations were proposed for compiling a methodology for studying artificial soil mixtures.
Soil organic matter (SOM) in arctic and boreal soils is the largest terrestrial reservoir of carbon. Increased SOM mineralisation under increased temperature has the potential to induce a massive ...release of CO2. Precise parameterisation of the response of arctic soils to increased temperatures is therefore crucial for correctly simulating our future climate. Here, we investigated the temperature response of SOM mineralisation in eight arctic soil profiles of Norway, Svalbard and Russia. Samples were collected at two depths from both mineral and organic soils, which were affected or not by permafrost and were incubated for 91 days at 4, 8, 12, and 16 °C. Temperature response was investigated through two parameters derived from a simple exponential model: the intensity of mineralisation, α, and the temperature sensitivity, Q10. For each sample, SOM quality was investigated by 13C-NMR, whereas bacterial and fungal community structure was characterised by T-RFLP and ARISA fingerprints, respectively. When estimated from the whole incubation period, α proved to be higher in deep permafrost samples than in shallow active layer ones due to the presence transient flushes of mineralisation in deep permafrost affected soils. At the end of the incubation period, after mineralization flushes had passed, neither α nor Q10 (averaging 1.28 ± 0.07) seemed to be affected by soil type (organic vs mineral soil), site, depth or permafrost. SOM composition and microbial community structure on the contrary where affected by site and soil type. Our results suggest that deep samples of permafrost affected soil contain a small pool of fast cycling carbon, which is quickly depleted after thawing. Once the mineralization flush had passed, the temperature response of permafrost affected soil proved to be relatively homogenous among sample types, suggesting that the use of a single temperature sensitivity parameter in land surface models for SOM decomposition in permafrost-affected soils is justified.
•Temperature response of SOM mineralization studied in profiles for 3 Arctic sites.•Initial mineralization intensity higher in permafrost than active layers.•Uniform Q10 among samples (1.21–1.43).•OM composition and microbial community structure site specific, not depth related.•OM and microbes not directly linked to mineralization intensity and Q10.
•Growth synchrony patterns of Siberian Scots pine populations are driven by climate.•Growth synchrony in sites with mineral soil has increased but decreased in peats.•High fire occurrence reduced ...synchrony in frequently burned sites since mid-1980s.•Growth suppressions allow reconstructing past fire occurrence.•Post-fire legacies last from 1-5 years depending on soil type, fire and tree features.
Wildfires are the main disturbance of boreal ecosystems, one of the largest reservoirs of terrestrial carbon. Two-thirds of boreal forests are in Siberia, where peatlands commonly appear mixed with mineral soils. Siberian forests are currently facing a dual shift in environmental conditions regarding climate change and increased fire activity. Therefore, assessing growth patterns of trees subjected to different disturbance regimes is essential to understand the impact of ongoing environmental changes on forest functioning. Following a dendroecological approach, we aimed at analyzing spatial synchrony (âC) patterns of trees subjected to different ecohydrological and fire disturbance conditions in forests of Pinus sylvestris of south-western Siberia. Furthermore, we assessed growth suppression as a proxy for fire occurrence based on tree-ring width chronologies after removing climate signals. Our results endorsed climate as the main driver of âC, which showed different trends depending on substrate type. A release of temperature constraints in the more temperature-limited peat soils led to decreasing âC from mid-1960s onwards, while the opposite pattern was found in mineral soils where stronger reliance on summer precipitation progressively increased âC. However, frequently burned stands suffered a sharp reduction in âC since 1980s likely due to the decoupling of growth from climate as a result of an increase in fire activity. Strong replication of growth suppressions supported by historical and palaeoecological records pointed to 1915, 1952, 1977, 1983, 2003 and 2012 as potential fire years. Post-fire legacies on tree growth after such fire events lasted from one to five years, although differences were modulated by soil type, fire event, growth rate prior fire and tree age. This study highlights the usefulness of addressing spatial synchrony in tree growth and past growth suppressions to disentangle the impacts of climate change and increased fire occurrence on boreal forests.
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